9/11 New York 2

FILE - In this Tuesday, Sept. 11, 2001 file photo, people run from a cloud of debris from the collapse of a World Trade Center tower in New York. (AP Photo/Suzanne Plunkett)

2001 AP

Policemen stand guard near the site of the World Trade Center in New York, Wednesday, Sept. 12, 2001. In the most devastating terrorist onslaught ever waged against the United States, knife-wielding hijackers crashed two airliners into the World Trade Center on Tuesday, toppling its twin 110-story towers. (AP Photo/Beth A. Keiser)

2001 AP

Deputy U.S. marshal Dominic Guadagnoli helps a women after she was injured in the terrorist attack on the World Trade Center in New York, Tuesday, Sept. 11, 2001. (AP Photo/Gulnara Samoilova)

2001 AP

The Statue of Liberty, right, stands at the entrance to New York Harbor as the twin towers of the World Trade Center burn in this view from Jersey City, N.J., Sept. 11, 2001. (AP Photo/Mike Derer)

2001 AP

Firefighters are dwarfed by debris at the site of the World Trade Center in New York Tuesday, Sept. 11, 2001. Planes crashed into the upper floors of the World Trade Center towers minutes apart Tuesday morning collapsing both 110-story buildings. (AP Photo/Graham Morrison)

2001 AP

Rescue workers remove debris from the rubble of the World Trade Center towers Thursday, Sept. 13, 2001, in New York. The search for survivors and the recovery of the victims continues since Tuesday's terrorist attack.(AP Photo/Beth A. Keiser, pool)

2001 AP

FILE - This Saturday morning, Sept. 15, 2001 file picture shows the Statue of Liberty from a vantage point in Jersey City, N.J., as the lower Manhattan skyline is shrouded in smoke following the Sept. 11 terrorist attacks on the World Trade Center in New York. (AP Photo/Dan Loh)

AP2001

People run from the collapse of World Trade Center Tower Tuesday, Sept. 11, 2001 in New York. (AP Photo/Suzanne Plunkett)

2001 AP

As dawn breaks over New York, smoke rises from lower Manhattan following the destruction of buildings at the World Trade Center in New York, Wednesday, Sept. 12, 2001. Two hijacked commercial aircraft crashed into the center's towers, which were previously visible looming over the buildings at left. (AP Photo/Charles Krupa)

2001 AP

Julie McDermott, center, walks with other victims as they make their way amid debris near the World Trade Center in New York Tuesday Sept. 11, 2001. In one of the most horrifying attacks ever against the United States, terrorists crashed two airliners into the World Trade Center in a deadly series of blows that brought down the twin 110-story towers. (AP Photo/Gulnara Samoilova)

2001 AP

People make their way amid debris near the World Trade Center in New York Tuesday Sept. 11, 2001. In one of the most horrifying attacks ever against the United States, terrorists crashed two airliners into the World Trade Center in a deadly series of blows that brought down the twin 110-story towers. (AP Photo/Gulnara Samoilova)

2001 AP

The south tower of New York's World Trade Center collapses Tuesday Sept. 11, 2001. In one of the most horrifying attacks ever against the United States, terrorists crashed two airliners into the World Trade Center in a deadly series of blows that brought down the twin 110-story towers. (AP Photo/Richard Drew)

2001 AP

Firefighters work in the rubble of the World Trade Center towers in New York, Wednesday, Sept. 12, 2001. The towers collapsed Tuesday after being struck by two commercial aircrafts in a terrorist attack. (AP Photo/Virgil Case)

2001 AP

Firefighters make their way through the rubble after terrorists crashed two airliners into the World Trade Center in a deadly series of blows Tuesday that brought down the twin 110-story towers in New York Tuesday, Sept. 11, 2001. (AP Photo/Shawn Baldwin)

2001 AP

A lone firefighter moves through piles of debris at the site of the World Trade Center in New York, Tuesday, Sept. 11, 2001. Two Planes crashed into the upper floors of the World Trade Center towers minutes apart Tuesday morning, collapsing both 110-story buildings. (AP Photo/Graham Morrison)

2001 AP

Firefighters walk away early Saturday morning Sept. 15, 2001, from the twisted metal and rubble left after Tuesday's terrorist attack that destroyed the World Trade Center in New York. (AP Photo/ VIctoria Arocho)

2001 AP

FILE - In this Sept. 2001 file photo, dust still covers the streets near ground zero as Associated Press photographer Amy Sancetta pushes her bike on the streets a few days after the terrorist attacks in New York. On Sept. 11, 2001, the Ohio-based national photographer was in New York City to cover her tenth the U.S. Open Tennis tournament. The desk had a report that a plane might have hit one of the World Trade Center towers, so she caught a cab downtown. While shooting, she heard a thunderous rumbling and watched through her lens as the tower's top "kind of cracked and started to fall in on itself." She managed to squeeze off only about a half-dozen frames before the tower disappeared behind a shiny, black skyscraper. With her subject gone, Sancetta's sports shooter instincts kicked in. When covering a basketball game, it's long lens for the far court, short lens for the near court. She whipped out her other camera with its 14mm wide-angle lens and began firing away. People were rushing past, buffeting her as they ran pell-mell from the rising debris cloud. (AP Photo)

AP2001

Bill Fennelly, a volunteer firefighter from Baldwin, N.Y., pauses for a moment at the World Trade Center collapse in New York, Thursday morning, Sept. 13, 2001. (AP Photo/Stephen Chernin)

2001 AP

An aerial view on Sept. 17 2001, shows the debris-clogged Winter Garden between the buildings of the World Financial Center near the World Trade Center which collapsed following the Sept. 11 terrorist attack. These surrounding buildings were heavily damaged by the debris and massive force of the falling twin towers. Clean-up efforts are expected to continue for months. (AP Photo/U.S. Navy, Chief Photographer's Mate Eric J. Tilford)

2001 AP

Flames and smoke pour from a building at the Pentagon Tuesday, Sept. 11, 2001, after a direct, devasting hit from an aircraft. (AP Photo/Mandatory Credit, Will Morris)

2001 AP

Rubble and ash fill lower Manhattan streets after two hijacked airliners were crashed into the towers of the World Trade Center in New York, Tuesday, Sept. 11, 2001. The planes crashed into the upper floors of both World Trade Center towers minutes apart collapsing the 110-story buildings. (AP Photo/Boudicon One)

2001 AP

Emergency personnel gather at the site of the World Trade Center in New York, Tuesday, Sept. 11, 2001. Two planes crashed into the upper floors of both World Trade Center towers minutes apart Tuesday morning, collapsing the 110-story buildings. (AP Photo/Graham Morrison)

2001 AP

The damaged west face of the Pentagon is shown is this aerial photo Friday, Sept. 14, 2001. (AP Photo/Department of Defense, Tech. Sgt. Cedric H. Rudisill)

2001 AP

People flee lower Manhattan across the Brooklyn Bridge in New York, Tuesday, Sept. 11, 2001, following a terrorist attack on the World Trade Center. (AP Photo/Daniel Shanken)

2001 AP

ADVANCE FOR USE LABOR DAY WEEKEND, SEPT. 3-5, 2011 AND THEREAFTER - FILE - In this Sept. 14, 2001 file photo, President George W. Bush, center, talks to former New York City Fire Commissioner Thomas Van Essen, right, wearing helmet, as New York Police Commissioner Bernard Kerik, left, and former New York City Mayor Rudolph Giuliani, foreground with back to camera, look on during a tour of the World Trade Center in New York. Sept. 11 defined one presidency. It still hangs over another. Every big ramification of that horrible day, two wars, tremendous debt, the unsolvable Guantanamo Bay prison, the hunt for Osama bin Laden, the dead still coming home at Dover, has bridged the decade from George W. Bush to Barack Obama. The White House, like the rest of the country, has been forever changed. (AP Photo/Doug Mills)

AP2001

Firemen are deployed near the site of the World Trade Center in New York, Wednesday, Sept. 12, 2001. In the most devastating terrorist onslaught ever waged against the United States, knife-wielding hijackers crashed two airliners into the World Trade Center on Tuesday, toppling its twin 110-story towers. (AP Photo/Mark Lennihan)

2001 AP

FILE - In this Sept. 13, 2001 file photo, an American flag flies over the rubble of the collapsed World Trade Center buidlings in New York. (AP Photo/Beth A. Keiser)

AP2001

Workers gather Wednesday, Sept. 12, 2001, to continue work at the site of the attack on the World Trade Center in New York. A large piece of the facade fallen from the one of the twin towers is in the background. (AP Photo/Amy Sancetta)

2001 AP

People run from the collapse of World Trade Center towers in New York, Tuesday, Sept. 11, 2001 after terrorists crashed two hijacked airliners into the World Trade Center and brought down the twin 110-story towers. (AP Photo/Suzanne Plunkett)

2001 AP

Emergency personnel carry an orange body bag with the remains of a victim of the World Trade Center crash from the rubble, Thursday, September 13, 2001. Two hijacked airliners were crashed into the towers of the World Trade Center on Tuesday, Sept. 11, destroying both buildings. (AP Photo/Bill Farrington)

2001 AP

A man coated with ash and debris from the collapse of the World Trade Center south tower coughs near City Hall in lower Manhattan Sept. 11, 2001. (AP Photo/Amy Sancetta)

2001 AP

President Bush is seen through the windows of the Oval Office of the White House in Washington, Tuesday, Sept. 11, 2001, as he addresses the nation about terrorist attacks at the World Trade Center and the Pentagon. (AP Photo/Doug Mills)